1. Field of the Invention
The present invention relates to a control unit used in a data processing device. The control unit controls an input/output port that the data processing unit uses to communicate with an external device. The present invention also relates to a method for switching input/output ports and to a storage medium storing a program for switching the input/output port.
2. Description of Related Art
There has been developed a variety of softwares for use in a data processing device. The data processing device includes a memory for storing the variety of softwares and an input/output ports for enabling the softwares to communicate with external devices, such as a printer and a scanner. Examples of the software include application softwares for executing processes using a screen and software drivers for driving the external devices via the input/output ports. Usually, the software drivers are individually installed on an operation system of the data processing device. Some of the softwares are designed to exclusively use only a certain designated input/output port. For example, only a printer driver for driving a printer is allowed to use a designated input/output port LPT1, for example. In this case, no other software can use the input/output port LPT1.